1.1 What Is pSOSystem?

pSOSystem is a modular, high-performance real-time operating system designed specifically for embedded microprocessors. It provides a complete multitasking environment based on open systems standards.

pSOSystem is designed to meet three overriding objectives:

• Performance
• Reliability
• Ease-of-Use

The result is a fast, deterministic, yet accessible system software solution. Accessible in this case translates to a minimal learning curve. pSOSystem is designed for quick startup on both custom and commercial hardware.

The pSOSystem software is supported by an integrated set of cross development tools that can reside on UNIX- or DOS-based computers. These tools can communicate with a target over a serial or TCP/IP network connection.

1.2 System Architecture

The pSOSystem software employs a modular architecture. It is built around the pSOS+ real-time multi-tasking kernel and a collection of companion software components. Software components are standard building blocks delivered as absolute position-independent code modules. They are standard parts in the sense that they are unchanged from one application to another. This black box technique eliminates maintenance by the user and assures reliability, because hundreds of applications execute the same, identical code.

Unlike most system software, a software component is not wired down to a piece of hardware. It makes no assumptions about the execution/target environment. Each software component utilizes a user-supplied configuration table that contains application- and hardware-related parameters to configure itself at startup.

Every component implements a logical collection of system calls. To the application developer, system calls appear as re-entrant C functions callable from an application. Any combination of components can be incorporated into a system to match your real-time design requirements. The pSOSystem components are listed below. NOTE: Certain components may not yet be available on all target processors. Check the release notes to see which pSOSystem components are available on your target.

• pSOS+ Real-time Multitasking Kernel. A field-proven, multitasking kernel that provides a responsive, efficient mechanism for coordinating the activities of your real-time system.
• pSOS+m Multiprocessor Multitasking Kernel. Extends the pSOS+ feature set to operate seamlessly across multiple, tightly-coupled or distributed processors.
• pNA+ TCP/IP Network Manager. A complete TCP/IP implemen-tation including gateway routing, UDP, ARP, and ICMP protocols; uses a standard socket interface that includes stream, datagram, and raw sockets.
• pRPC+ Remote Procedure Call Library. Offers SUN-compatible RPC and XDR services; allows you to build distributed applications using the familiar C procedure paradigm.
• pHILE+ File System Manager. Gives efficient access to mass storage devices, both local and on a network. Includes support for CD-ROM devices, MS-DOS compatible floppy disks, and a high-speed proprietary file system. When used in conjunction with the pNA+ component and the pRPC+ subcomponent, offers client-side NFS services.
• pREPC+ ANSI C Standard Library. Provides familiar ANSI C run-time functions such as printf(), scanf(), and so forth, in the target environment.

Figure 1-1 illustrates the pSOSystem environment.

In addition to these core components, pSOSystem includes the following:

• Networking protocols including SNMP, FTP, Telnet, TFTP, NFS, and STREAMS
• Run-time loader
• User application shell
• Support for C++ applications
• Boot ROMs
• Pre-configured versions of pSOSystem for popular commercial hardware
• pSOSystem templates for custom configurations
• Chip-level device drivers
• Sample applications

This manual focuses on explaining pSOSystem core components. Other parts of the pSOSystem environment are described in the pSOSystem Programmer's Reference and in the pSOSystem Getting Started manual.

1.3 Integrated Development Environment

The pSOSystem integrated cross-development environment can reside on a UNIX- or DOS-based computer. It includes C and C++ optimizing compilers, a target CPU simulator, a pSOS+ OS simulator, and a cross-debug solution that supports source- and system-level debugging.

The pSOSystem debugging environment centers on the pROBE+ system-level debugger and optional high-level debugger. The high-level debugger executes on your host computer and works in conjunction with the pROBE+ system-level debugger, which runs on a target system.

The combination of the pROBE+ debugger and optional host debugger provides a multitasking debug solution that features:

• A sophisticated mouse and window user interface.
• Automatic tracking of program execution through source code files.
• Traces and breaks on high-level language statements.
• Breaks on task state changes and operating system calls.
• Monitoring of language variables and system-level objects such as tasks, queues and semaphores.
• Profiling for performance tuning and analysis.
• System and task debug modes.
• The ability to debug optimized code.

The pROBE+ debugger, in addition to acting as a back end for a high-level debugger on the host, can function as a standalone target-resident debugger that can accompany the final product to provide a field maintenance capability.

The pROBE+ debugger and other pSOSystem development tools are described in other manuals. See ``Related Documentation" in About This Manual.